伪码定距及数字相关技术研究

【作者】 王李军；

【导师】 赵惠昌；

【作者基本信息】 南京理工大学 ， 信号与信息处理， 2003， 硕士

【摘要】 伪码引信是利用伪随机序列的自相关函数类似于白噪声相关函数的随机特性而工作的，这种引信距离截止特性好，抗干扰能力强，是一种性能优越的无线电引信。本文深入分析了伪码引信的定距原理和定距性能，在此基础上给出了伪码的精确定距技术方案，并分析了该方案的定距性能。 根据信号的检测和估计理论，文中分析了数字相关器实现伪码信号接收的最佳模型，从理论上计算了在不同的虚警概率下，检测概率随输入信噪比的变化曲线，并分析了Doppler效应对伪码相关接收的影响。详细分析了数字相关器的实现原理和实现结构，给出了经典结构和修正结构两种结构的实现形式，分别对两种结构进行了仿真分析，并对不同的实现形式进行了对比。为了增加系统工作的可靠性，本系统采用4倍于伪码速率的采样频率。 文中利用Xilinx公司的Foundation Series软件，详细设计了两种结构的数字相关器，经典结构的数字相关器以加法器的设计为重点，设计并仿真了一般结构和3-2压缩结构的加法器，针对本系统文中还提出了一种快速计算加法的设计思想，综合后比前两种结构在性能上有明显的提高；修正结构的数字相关器是基于模块化的思想设计实现的，并以一个码元的不同延时点为例，详细分析了相关器的性能。最后用FPGA芯片设计并硬件实现了修正结构的数字相关器，这种结构的数字相关器具有很好的工作性能。更多还原

【Abstract】 The autocorrelation function of the PN code is similar to that of the white noise, which has the randomicity. The PN code phase modulation fuze just works on the basis of this characteristic. The fuse, having excellent cut-off performance of the distance and strong anti-jamming capability, is one of the radio fuze of the predominant performance. In this paper, based on the deep analysis of distance-determination with the PN code, the scheme of accurate distance-determination is introduced, and its performance is analyzed.In this paper, according to the theory of signal detection and estimation, the optimal receiver pattern of PN code signal is introduced and theoretically, the relation curve of the probability of the correct detection with the input S/N ratio under the different probabilities of false alarm is illuminated. Meanwhile, the influence of Doppler effect on PN correlation is analyzed. The realization principle and structure of the digital correlator is analyzed, and then the realization form of the classical and modificatory structure of the correlator is introduced. To enhance the system reliability, the sample frequency of the digital correlator is four times as much as that of the PN code.The digital correlators of the two structures are designed with the Foundation Series 3.1 Xlinx design tools software. The classical structure emphasizes on the design of the adder, whose general form and 3-2 compressor structure are designed and analyzed. In this system, an express addition method is put forward, and its synthesis performance proves that it is superior to the two structures mentioned above. Based on the idea of modularization, the digital correlator of the modificatory structure is designed. Then, taking the different delays of a code chip for example, the performance of the correlator is analyzed with circumstances. Eventually, the digital correlator of the modificatory structure is designed and realized by FPGA, and it manifests very high and reliable correlative performance.更多还原